Engineering Commons^™

Simplified Design Of Thin-Film Polarizing Beam Splitter Using Embedded Symmetric Trilayer Stack, R. M.A. Azzam

Electrical Engineering Faculty Publications

An analytically tractable design procedure is presented for a polarizing beam splitter (PBS) that uses frustrated total internal reflection and optical tunneling by a symmetric LHL trilayer thin-film stack embedded in a high-index prism. Considerable simplification arises when the refractive index of the high-index center layer H matches the refractive index of the prism and its thickness is quarter-wave. This leads to a cube design in which zero reflection for the p polarization is achieved at a 45 degrees angle of incidence independent of the thicknesses of the identical symmetric low-index tunnel layers L and L. Arbitrarily high reflectance for …

Quantifying Performance Of Cooperative Diversity Using The Sampling Property Of A Delta Function, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we present a simple approach to evaluating the performance of amplify-and-forward cooperative diversity. The �-function can be asymptotically reduced to a delta (impulse) function. We extend the result to cooperative networks in fading channels. The proposed approach introduces a simple technique to evaluate the performance of complex networks by sampling.

An Enzymatic Treatment Of Soil-Bound Prions Effectively Inhibits Replication, Samuel Saunders, Jason C. Bartz, Kurt C. Vercauteren, Shannon L. Bartelt-Hunt

Department of Civil and Environmental Engineering: Faculty Publications

Chronic wasting disease (CWD) and scrapie can be transmitted through indirect environmental routes, possibly via soil, and a practical decontamination strategy for prion-contaminated soil is currently unavailable. In the laboratory, an enzymatic treatment under environmentally relevant conditions (22°C, pH 7.4) can degrade soil-bound PrPSc below the limits of Western blot detection. We developed and used a quantitative serial protein misfolding cyclic amplification (PMCA) protocol to characterize the amplification efficiency of treated soil samples relative to controls of known infectious titer. Our results suggest large (104- to >106-fold) decreases in soil-bound prion infectivity following enzyme treatment, demonstrating that a mild enzymatic …

Transport Of Trace Elements In Runoff From Unamended And Pond‐Ash Amended Feedlot Surfaces, Jason R. Vogel, John E. Gilley, Gary L. Cottrell, Brian L. Woodbury, Elaine D. Berry, Roger Eigenberg

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The use of pond ash (fly ash that has been placed in evaporative ponds for storage and subsequently dewatered) for feedlot surfaces provides a drier environment for livestock and furnishes economic benefits. However, pond ash is known to have high concentrations of trace elements, and the runoff water‐quality effects of feedlot surfaces amended with pond ash are not well defined. For this study, two experimental units (plots) were established in eight feedlot pens. Four of the pens contained unamended soil surfaces, and the remaining four pens had pond‐ash amended surfaces. Before each test, unconsolidated surface material was removed from four …

Sustainable Oxygen: A Low Power Approach For Providing Emergency Medical Oxygen For Spacecraft And Hospitals In Developing Countries, Anndee L. Huff, Evan Rhead, Zdenek Zumr, Evan A. Thomas

Mechanical and Materials Engineering Faculty Publications and Presentations

An oxygen concentrator targeting an 80% reduction in power demand over commercial systems is being developed using a pressure swing adsorption process. This system is targeted for a service interval five times longer than commercial systems, and is tolerant to high humidity environments- the leading cause of device failure in developing countries. This system could provide emergency medical oxygen in a spacecraft without increasing oxygen concentration in the vehicle. Flight surgeons seek this capability, but presently, there is no system that meets power, size, and delivery rate requirements. This type of system is also well suited for medical oxygen in …

Refrigerant Mass Migration Modeling And Simulation For Air Conditioning Systems, Bin Li, Steffen Peuker, Predrag S. Hrnjak, Andrew G. Alleyne

Mechanical Engineering

Refrigerant mass migration and redistribution are regarded as key factors affecting the cycling performance of air conditioning and refrigeration systems. A dynamic model of an R134a automotive air conditioning system is presented as an example in this paper to capture the refrigerant migration during compressor shut-down and start-up operations. Model validation against experimental data demonstrates the capabilities of the modeling approach in predicting the refrigerant mass migration among the components during shut-down, and the resulting refrigerant redistribution behaviors during start-up. These results represent the first refrigerant mass migration prediction in a validated dynamic system model. In addition, the potential of …

Vibroacoustic Study Of Circular Cylindrical Tubes In Roller Coaster Rails, Joshua I. Davis, Charles Birdsong, Harold M. Cota

Mechanical Engineering

Excessive noise generated by roller coasters during operation is a significant issue for amusement parks located near residential and business districts. Previous work showed that filling the rails with sand and pea gravel can provide noise reduction levels of up to 10 and 15 decibels. However, using damping materials may require additional support structures to accommodate the weight increase and, consequently, raise installation costs. This paper presents field results that characterize sound and vibration of roller coasters with different rail geometry and fill. Finite element modeling is used to compute the theoretical natural frequencies and mode shapes of a typical …

The Human Dimension Of Systemic Department-Level Change: A Change Agent’S Retrospective On A Case Of Reform, Linda Vanasupa

Materials Engineering

This paper represents a narrative of the process of department-level reform through the eyes of the initiating agent of change. Over the course of reform, our program has grown by 40%, primarily through retaining students. We exhibit a 10% net important rate of engineering students in the first two years of the curriculum relative to the college’s 5% mean export rate. Student freshmen SAT scores also indicate that we are attracting students with more balanced learning interests. The design of our Department Level Reform grant was to advance the knowledge of how to design engineering learning experiences that accomplish two …

Effect Of Palletized Box Offset On Compression Strength Of Unitized And Stacked Empty Corrugated Fiberboard Boxes, S. Paul Singh, Jay Singh, Koushik Saha

Industrial Technology and Packaging

The purpose of this study was to evaluate the effect of pallet type, tie-sheet and stack configuration on compression strength of a palletized load of boxes. Four boxes made from similar board grade and different dimensions were selected for this study. The column stack configuration which represented the control was compared with the 3 stack configurations either on a CHEP® or GMA pallet. The unitized load either had a tie-sheet in between layers or no tie-sheet between layers of boxes on the respective pallets, for compression strength comparison with the control unitized load represented by a column stack configuration. This …

Effect Of Horizontal Offset On Vertical Compression Strength Of Stacked Corrugated Fiberboard Boxes, Jay Singh, S. Paul Singh, Koushik Saha

Industrial Technology and Packaging

The purpose of this study was to evaluate the effect of horizontal offset on the compression strength of stacked box configurations. Four different boxes of varying sizes and similar board combinations, made from similar flute but different manufacturers were studied. The single box compression strength for each type of box was determined to represent as the control for this study. The compression strength of control boxes were compared to overall strength of a three-high stack and in three different offset configurations. In addition a set of perfectly aligned boxes were compared to overall strength of a three-high stack and in …

A Probabilistic Analysis Of A Simplified Biogeography-Based Optimization Algorithm, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Biogeography-based optimization (BBO) is a population-based evolutionary algorithm (EA) that is based on the mathematics of biogeography. Biogeography is the study of the geographical distribution of biological organisms. We present a simplified version of BBO and perform an approximate analysis of the BBO population using probability theory. Our analysis provides approximate values for the expected number of generations before the population's best solution improves, and the expected amount of improvement. These expected values are functions of the population size. We quantify three behaviors as the population size increases: first, we see that the best solution in the initial randomly generated …

On Active Disturbance Rejection Based Control Design For Supercomputing Rf Cavities, John Vincent, Dan Morris, Nathan Usher, Zhiqiang Gao, Shen Zhao, Achille Nicoletti, Qinling Zheng

Electrical and Computer Engineering Faculty Publications

Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control …

A Silicon Nanoparticle-Based Polymeric Nano-Composite Material For Glucose Sensing, Qiang Liu, Munir H. Nayfeh, Siu-Tung Yau

Electrical and Computer Engineering Faculty Publications

A novel non-enzyme glucose sensing material has been prepared by incorporating ultrasmall (1–3 nm) silicon nanoparticles in polyaniline, a conducting polymer, as a nano-composite material (NCM). When deposited on electrodes, the composite material with three-dimensional loading of the nanoparticles showed a significantly enhanced amperometric response to glucose, compared to the nanoparticles deposited on bare electrodes and electrodes immobilized with the enzyme, glucose oxidase. The linear range of the glucose response of NCM electrodes covered both the hypo- and hyper-glycaemic glucose levels. The sensitivity of the NCM electrodes was 2.5 μA cm⁻² mM⁻¹. The NCM electrodes’ selectivity for …

On Active Disturbance Rejection Based Control Design For Superconducting Rf Cavities, John Vincent, Dan Morris, Nathan Usher, Zhiqiang Gao, Shen Zhaob, Achille Nicoletti, Qinling Zheng

Electrical and Computer Engineering Faculty Publications

Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control technique …

A Hybrid Agent Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yew-Soon Ong, Akejariyawong Tapanuj

Research Collection School Of Computing and Information Systems

This paper presents a hybrid agent architecture that integrates the behaviours of BDI agents, specifically desire and intention, with a neural network based reinforcement learner known as Temporal DifferenceFusion Architecture for Learning and COgNition (TD-FALCON). With the explicit maintenance of goals, the agent performs reinforcement learning with the awareness of its objectives instead of relying on external reinforcement signals. More importantly, the intention module equips the hybrid architecture with deliberative planning capabilities, enabling the agent to purposefully maintain an agenda of actions to perform and reducing the need of constantly sensing the environment. Through reinforcement learning, plans can also be …

Real-World Parameter Tuning Using Factorial Design With Parameter Decomposition, Aldy Gunawan, Hoong Chuin Lau, Elaine Wong

Research Collection School Of Computing and Information Systems

In this paper, we explore the idea of improving the efficiency of factorial design for parameter tuning of metaheuristics. In a standard full factorial design, the number of runs increases exponentially as the number of parameters. To reduce the parameter search space, one option is to first partition parameters into disjoint categories. While this may be done manually based on user guidance, an automated approach proposed in this paper is to apply a fractional factorial design to partition parameters based on their main effects where each partition is then tuned independently. With a careful choice of fractional design, our approach …

The Effects Of System Reliability And Time Pressure On Unoccupied Aircraft Systems Operator Performance And Mental Workload, Rania Wageh Ghatas

Doctoral Dissertations and Master's Theses

Unoccupied Aircraft Systems (UAS) are in the midst of aviation`s next generation. UAS are being utilized at an increasing rate by military and security operations and are becoming widely popular in usage from search and rescue and weather research to homeland security and border patrol. The Federal Aviation Administration (FAA) is currently working to define acceptable UAS performance standards and procedures for routine access for their use in the National Airspace System (NAS). This study examined the effects of system reliability and time pressure on unoccupied aircraft systems operator performance and mental workload. Twenty-four undergraduate and graduate students, male and …

The Development And Deployment Of A Nexrad Education / Training Module For Use By General Aviation Pilots, Erin Anne Roberts

Doctoral Dissertations and Master's Theses

The purpose of this research was to investigate whether an education/ training module on NEXRAD and its products developed using Instructional Systems design criteria would be effective for General aviation pilots. Numerous studies have documented that General Aviation pilots are in need of additional education and training on weather concepts. A thorough needs analysis and literature review determined that training was the best way to address this problem. An education/training module and assessments were developed from scratch using strict instructional design criteria. Sixty students from Embry-Riddle Aeronautical University participated in live testing of the module. Participants were separated into control …

Striation-Based Beamforming For Estimating The Waveguide Invariant With Passive Sonar, Lisa M. Zurk, Daniel Rouseff

Electrical and Computer Engineering Faculty Publications and Presentations

The waveguide invariant summarizes the pattern of constructive and destructive interference between acoustic modes propagating in the ocean waveguide. For many sonar signal-processing schemes, it is essential to know the correct numerical value for the waveguide invariant. While conventional beamforming can estimate the ratio between the waveguide invariant and the range to the source, it cannot unambiguously separate the two terms. In the present work, striationbased beamforming is developed. It is shown that the striation-based beamformer can be used to produce an estimate for the waveguide invariant that is independent of the range. Simulation results are presented.

Differential Responses Of Targeted Lung Redox Enzymes To Rat Exposure To 60 Or 85% Oxygen, Zhuohui Gan, David L. Roerig, Anne V. Clough, Said H. Audi

Biomedical Engineering Faculty Research and Publications

Rat exposure to 60% O₂ (hyper-60) or 85% O₂ (hyper-85) for 7 days confers susceptibility or tolerance, respectively, of the otherwise lethal effects of exposure to 100% O₂. The objective of this study was to determine whether activities of the antioxidant cytosolic enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) and mitochondrial complex III are differentially altered in hyper-60 and hyper-85 lungs. Duroquinone (DQ), an NQO1 substrate, or its hydroquinone (DQH₂), a complex III substrate, was infused into the arterial inflow of isolated, perfused lungs, and the venous efflux rates of DQH₂ and DQ were measured. …

Noninvasive Imaging Of The Human Rod Photoreceptor Mosaic Using A Confocal Adaptive Optics Scanning Ophthalmoscope, Alfredo Dubra, Yusufu N. Sulai, Jennifer L. Norris, Robert F. Cooper, Adam M. Dubis, David R. Williams, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

The rod photoreceptors are implicated in a number of devastating retinal diseases. However, routine imaging of these cells has remained elusive, even with the advent of adaptive optics imaging. Here, we present the first in vivo images of the contiguous rod photoreceptor mosaic in nine healthy human subjects. The images were collected with three different confocal adaptive optics scanning ophthalmoscopes at two different institutions, using 680 and 775 nm superluminescent diodes for illumination. Estimates of photoreceptor density and rod:cone ratios in the 5°–15° retinal eccentricity range are consistent with histological findings, confirming our ability to resolve the rod mosaic by …

Using Laser Scanning Cytometry To Investigate The Transport Of Nano-Scale Particles In Porous Media, Ryan May

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The increased production of nanomaterials in recent years has been unprecedented. Given their potential toxicity, understanding the mechanisms controlling the transport of nanoparticles in the subsurface is important. In this study, a technique was developed for using a Laser Scanning Cytometer (LSC) to visualize and quantify the stable attachment of nano-scale particles. Experiments using three different size particles, 510 nm, 210 nm and 57 nm, in conjunction with a flow cell system containing saturated glass beads under varied injection duration, solution chemistry, Darcy velocity and solids content were performed. A technique for using the LSC data to develop spatial distributions …

Effect Of Information On Driver's Risk At The Onset Of Yellow, Nathaniel P. Burnett

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Intersection crashes average approximately 8,500 fatal and 900,000 injury accidents a year (1). At the onset of yellow at a high speed signalized intersection, a driver may encounter a region of the intersection approach, where they can neither stop safely nor be able to clear the intersection before the red indication. A wrong decision to stop when it would have been safer to proceed can lead to a severe rear-end collision. Conversely, a wrong decision to proceed through the intersection could lead to the driver running the red light and possibly causing a right angle collision. The traditional …

Computational Microstructure Modeling Of Asphalt Mixtures Subjected To Rate-Dependent Fracture, Francisco Aragao

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Computational microstructure models have been actively pursued by the pavement mechanics community as a promising and advantageous alternative to limited analytical and semi-empirical modeling approaches. The primary goal of this research is to develop a computational microstructure modeling framework that will eventually allow researchers and practitioners of the pavement mechanics community to evaluate the effects of constituents and mix design characteristics (some of the key factors directly affecting the quality of the pavement structures) on the mechanical responses of asphalt mixtures. To that end, the mixtures are modeled as heterogeneous materials with inelastic mechanical behavior. To account for the complex …

Evaluation Of The In-Service Safety Performance Of Safety-Shape And Vertical Concrete Barriers, Francisco Daniel Albuquerque

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Roadside concrete barriers have been widely used to protect errant motorists from hitting roadside hazards or obstacles. Two concrete barrier profiles, vertical and safety-shape, have been used for this purpose. The safety-shape profile has been shown to produce excessive vehicle climbing which tends to increase rollover propensity. The vertical profile, on the other hand, does not cause vehicle climbing, but it does produce higher lateral forces which may produce higher injury levels.

The objective of this research is to investigate which barrier profile is the safest based on real-world vehicle crash data. The safest barrier profile is defined as the …

Delayed Composite Action Coupled With Post-Tensioning For Cast In Place Bridge Deck Systems, Nathanael J. Toenies

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Cast-in-place bridge decks are known to have transverse cracking early in the life of the bridge due to shrinkage and temperature effects. The cracks result from immediate composite behavior between the girder and the deck. For steel bridges, this bond is caused by shear studs welded to the steel beams and embedded in the cast-in-place deck. Prevention or closure of these cracks could greatly increase the durability of the bridge.

The following research focuses on introducing a system that will have delayed composite action, allowing strain in the concrete before it becomes composite with the girder. The system is meant …

A Wind Tunnel Technique For The Identification Of Ship Airwake/Rotor Downwash Coupling, Stargel R. Doane

Mechanical & Aerospace Engineering Theses & Dissertations

A wind tunnel study is performed to analyze the interaction between ship airwakes and helicopter rotor downwash. This interaction is of interest to naval aviators and researchers as this phenomenon is thought to limit helicopter flight envelopes and increase the overall difficulty of maritime rotorcraft operations. In this study, a 1/50th scale simplified naval frigate model and appropriately scaled rotor model are used for all experimental work. A rotor thrust survey was conducted in the immediate vicinity of the landing deck. Two dimensional and stereo particle image velocimetry surveys and rotor thrust measurements with various rotor and ship configurations were …

Excitation-Induced Ge Quantum Dot Growth On Si(100)-2x1 By Pulsed Laser Deposition, Ali Oguz Er

Physics Theses & Dissertations

Self-assembled Ge quantum dots (QD) are grown on Si(100)-(2×1) with laser excitation during growth processes by pulsed laser deposition (PLD). In situ reflection-high energy electron diffraction (RHEED) and post-deposition atomic force microscopy (AFM) are used to study the growth dynamics and morphology of the QDs. A Q-switched Nd:YAG laser (λ = 1064 nm, 40 ns pulse width, 5 J/cm² fluence, and 10 Hz repetition rate) were used to ablate germanium and irradiate the silicon substrate. Ge QD formation on Si(100)-(2×1) with different substrate temperatures and excitation laser energy densities was studied. The excitation laser reduces the epitaxial growth temperature …

Using The Web Infrastructure For Real Time Recovery Of Missing Web Pages, Martin Klein

Computer Science Theses & Dissertations

Given the dynamic nature of the World Wide Web, missing web pages, or "404 Page not Found" responses, are part of our web browsing experience. It is our intuition that information on the web is rarely completely lost, it is just missing. In whole or in part, content often moves from one URI to another and hence it just needs to be (re-)discovered. We evaluate several methods for a \justin- time" approach to web page preservation. We investigate the suitability of lexical signatures and web page titles to rediscover missing content. It is understood that web pages change over time …

A Framework For Dynamic Traffic Monitoring Using Vehicular Ad-Hoc Networks, Mohammad Hadi Arbabi

Computer Science Theses & Dissertations

Traffic management centers (TMCs) need high-quality data regarding the status of roadways for monitoring and delivering up-to-date traffic conditions to the traveling public. Currently this data is measured at static points on the roadway using technologies that have significant maintenance requirements. To obtain an accurate picture of traffic on any road section at any time requires a real-time probe of vehicles traveling in that section. We envision a near-term future where network communication devices are commonly included in new vehicles. These devices will allow vehicles to form vehicular networks allowing communication among themselves, other vehicles, and roadside units (RSUs) to …